Poor surface finish from PEI - any alternatives?  

Re: Poor surface finish from PEI - any alternatives?

Well, if if you don't mind some manual steps steps before each print, printing on glass is possible even with the PINDA on the MK2. see the video here:

With respect to the trouble of getting PETG prints off your bed, did you try the trick with dripping a bit of Isopropyl alcohol around its edges? It creeps under the prints and makes it easier to remove. Any remaining alcohol can then be used to wipe the bed down in preparation for your next print.

Re: Poor surface finish from PEI - any alternatives?

Well, if if you don't mind some manual steps steps before each print, printing on glass is possible even with the PINDA on the MK2. see the video here: ...

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this is a pretty decent idea: preparing the start script inside the gcode to do the meshbed levelling, pause two minutes and let the user assemble the glass sheet with some maulys and continue the gcode with an Z offset that represents the the thickness of the glass.
personally I would modify the start script to wait a few minutes longer and I would add +5°C to the bed temperature (or maybe more, depending on the thickness of the glass).

Re: Poor surface finish from PEI - any alternatives?

That does sound very reasonable indeed. And the mirror like surface finish you get from printing on glass is nice. Me personally, I am rather content with the PEI atm. So much so, that i stuck a spare PEI sheet on my UM2+ glas bed.

Re: Poor surface finish from PEI - any alternatives?

Mentioned here also, https://mattshub.com/2017/04/11/printing-on-glass/ .

This is something i will try. Sometimes i really want that smooth look on the bottom layer. My PEI is a bit uneven with bumps. Not much but anyway.

Re: Poor surface finish from PEI - any alternatives?

Even though I'm using a rounded spatula, I'm still scuffing the PEI print surface, as I'm printing a lot of flat PETG components that are hard to remove.I first initially prepped the PEI bed by scuffing it up with 2000 grit sandpaper in a circular fashion, enough to get a cloudy finish. Then I cleaned it with alcohol and let it set until it dried.

Depending on what I am printing determines how I clean it now after it was prepped. If I print with PLA I use alcohol. Once it is dry, then I start my print. With PETG and ABS I use blue windex (do not use alcohol, it will cause it to stick-stuck), cleaning similarly how I do it with the alcohol. Once dry, I start my print.

I have zero issues getting things to come off. A little trick with getting prints off though, without damaging the sheet is don't apply manual pressure. Even with a curved spatular or even one like the Buildtak one, you still end up inadvertently applying a slight amount of pressure downward on the bed. That manual pressure, prying is what damages the bed. Use a rubber mallet (not a hammer, must be a rubber mallet), position the corner of the spatula as best close/underneath you can get and give the handle of it a light tap. It just loosens up and pops off. Don't hammer it, don't pry with a forced amount of pressure, just a light tap. For larger pieces I just need to get a slight corner up, then can slip it under and around the rest but for the most part they pop off easily. No damage to the part or the bed.

Re: Poor surface finish from PEI - any alternatives?

I print a lot with PET on Prusa PEI sheet and as Shinlocke, I use windows cleaner before printing. Just a lite puff and a wipe off, let it dry and then print.
I wait until the bed is cooled to below 70-60 degree before removing the print. If the bed gets cold the prints sticks again and I set it to 40 degrees before attempting to remove the prints.
Don't force the prints off, just get a corner free and with little force the print pops off.

Before windows cleaner I used soap water, but if it gets to concentrated adhesion will get too weak and the print won't stick during printing.